Tappet



Dec. 11, 1934. w D CQRLETT 1,983,735

TAPPET Filed Oct. 5, 1932 Patented Dec. 11, 1934 UNITED STATES PATENTOFFICE TAPPET Application October 5,

4 Claims.

This invention relates to a valve tappet and to similar articles and hasfor one object to provide a valve tappet formed of a single piece, inwhich the head may be chilled to have satisfactory wearing qualities andin which the remainder of the tappet is formed integrally with the headin a single operation. Another object is toprovide a valve tappet orsimilar member which is hollow and which has sufficient structuralstrength, and in which the wearing head and the portion of the tappetwhich is attached to any other part, as well as the body of the tappet,are all formed integrally. Another object is to make a valve tappet ofsuch shape that it will be, in its normal operation, readily andcertainly lubricated. Another object is to form a tappet in which thebodydiameter is the same as, or larger than, that of the hardenedcamcontacting head, as distinguished from the common mushroom type oftappet.

Other objects will appear from time to time in the specification andclaims.

My invention is illustrated more or less diagrammatically in theaccompanying drawing, wherein- Figure 1 is a diagrammatic sectionalview, showing a tappet in position in an engine;

Figure 2 is a longitudinal cross section of the tappet, taken at line2-2 of Figure 1;

Figure 3 is a transverse section taken at line 33 of Figure 2;

Figure 4 is a section similar to Figure 2, showing a modified form;

Figure 5 is a transverse section taken at line ,55 of Figure 4;

Figure 6 is a plan view, showing one part of a mold in plan, with thecomplete pattern in position within the mold;

Like parts are designated by like characters throughout thespecification and. drawing.-

A is a tappet guide of any suitable form, perforated as at A B is a camwhich may be of any suitable design and is rotated so as to move thetappet. It is in contact with the lower or working face of the.

tappet. v

The tappet is formed of a generally cylindrical body C, ported as at Cand provided with a closed end C which provides a working face withwhich the cam is in contact. At its opposite end the generallycylindrical tappet is provided with a closure or end portion C which isprovided with an integrally threaded opening or perforation C About theperforation C there is a reduced extension or neck C. For purposes 1932,Serial No. 636,412

of strength, one or more circumferential ribs C may be formed about theinterior of the tappet, as shown for example in Figures 2 to 5,inclusive. For some purposes it is desirable to add one or morelongitudinal ribs C These are shown in the form of the device appearingin Figures 2 and 3, in which the circumferential rib C is also shown.The tappet may have seated at its threaded end C any form of attachment,indicated generally as at D, which may contact a push rod, valve stem orany other member, indicated diagrammatically at D in Figure 1. Thedetails of these parts or of other parts which might be attached to thetappet form no essential part of the present invention and will not befurther described. 1

While the tappet of this invention might be formed in any suitablemanner, it is economical to cast it as a single piece, in a singleoperation, so that the tappet shown in Figures 1 to 5, inclusive, iscast as a unit. One form of mold is indicated in plan in Figure 6. Asthere shown, a cast iron chill place E is arranged so that it willcontact the end faces or heads C of the tappet when the latter is cast.A green sand" mold F is formed in any suitable contour or in anysuitable manner, and is provided with a gate F having branches Fcommunicating with the individual tappet molds, by means of which metalmay flow to form the individual tappets. A pattern of suitable form isfirst made and this may be made to form a single tappet or a number, asshown in the drawing. In any event, it is used to shape the sand to formone or more tappet cavities F After the mold has been so shaped, a corewhich has been separately made is inserted in the tappet cavities. Asshown the core is multiple, to be used in making a number of tappetssimultaneously. It comprises the rounded portions G, provided. withcircular grooves G to form the circumferential ribs C", and withprotruding portions G G to form the ports C on one side. of each of thetappets, and the members (3- also serve to join together the severalportions G. Shorter extending members G are formed on each of themembers G and these serve to form the other ports 0 After. the two partsof the sand mold have been formed with the-tappet cavities and withportions to receive the core and particularly to receive the members Gof the core, the latter is put in place in one part of the mold. Theother part of the mold is then secured in place and the metal may bepoured. When it is hard, the mold is removed, the cores are broken upand fall out-or are removed from the tappet 55 castings which are thenfinished and may be thereafter drilled and tapped to provide thethreaded perforations C It will be realized that whereas I have herewithshown and described a practical operative device, nevertheless manychanges might be made in the size, shape, and number and disposition ofparts, without departing from the spirit of my invention, and I wish,therefore, that my showing be taken as in a sense diagrammatic.

In particular the tappet may be used without tapping the upper end toreceive an adjusting screw or other attaching part. It may be so madethat the upper end is closed and treated to receive the thrust end of avalve or push rod. Such an arrangement is useful in connection withnonadjustable tappets.

The construction of the tappet above described provides a, greaterstrength on the cam contacting face by reason of the support which thecylindrical body portion gives to the edges of the cam face. Thecylindrical body portion being, larger than the shaft portion of theordinary mushroom type of tappet, has a greater bearing surface than themushroom type and the tapped hole in which the tappet is connected toanother part is larger than would be the case with the mushroom type, byreason of the greater section due to the enlarged cylindrical body.Because the diameter of the head is the same as that of the cylindricalbody, the tappet can be removed from the motor block without removingthe cam shaft.

The provisionof ports provides for lightness, reducing the mass of metaland consequently the weight of the tappet. It also provides forlubrication, as lubricant will be splashed into and will otherwise reachthe interior of the tappet and since the tappet is made in a singlepiece instead of built up in a plurality of pieces, the cost is reducedand danger of coming apart or separation which occurs in a built-uptappet is elimi nated. V

The use and operation of my invention are as follows:

When the tappet of this invention is used, it will have been made in theproper size and will be inserted in an engine. The working end or faceis positioned so as to be in contact with or actuated by a cam and itsother end is connected in any suitable manner with a valve, a push rod,or any other mechanism desired. In the form shown, the end of the tappetaway from the working face is provided with a threaded perforation ordepression and into this may be seated a push rod, a valve stem or anyother connection or connecting member that is desirable. In the engineoperation, the tappet is moved by the cam and when the cam face recedes,it returns, following the cam in and cut. As it moves outward, the lowerportions of the ports are exposed below the guide and lubrication entersthe ports. As the tappet moves in or up again, so that the ports areclosed by the guide, the lubricant within the hollow tappet is movedabout and splashes out more or less through any and all of the ports andso lubricates the tappet and guide and thus provides a more adequatedegree of lubrication for the tappet than is possible with a solidtappet. The parts may be so proportioned that the upper ports areuncovered during the extreme inner movement of the tappet, so that insome cases both the upper and lower ports will be alternately uncoveredand covered and while uncovered, lubricant will enter them and providethe lubrication just mentioned.

Circulation of air also occurs through the ports and through the hollowtappet so that an additional cooling effect is provided. ,7

In tappets which have heads larger than the body of the tappet, in thecase of breakage, the tappet cannot be removed except by removing thecam shaft and then dropping the tappets out. In the tappet of thisinvention, since the head is no larger than the body, in case for anyreason it is necessary to remove the tappets, they may be moved bymerely pulling them out away from the cam shaft and it is not necessary,therefore, to take down the engine or to move or remove the cam shaft orcams.

Where tappets are made with enlarged heads, breakage most frequentlyoccurs at or near the edges of the enlarged head. This is due to thefact that the edges are thinned and unsupported. In the tappet of thepresent invention, since the head is not enlarged and since its diameteris the same as the outer diameter of the cylinder portion of the tappet,the outer edges of the head are completely supported by the cylindricalbody, and the head is thus stronger and less liable to breakage thanwould be the case where the edges of the head are unsupported as in thetypical tappet in which the head is larger than the shaft.

The operation of forming the tappets which permits the making of aninexpensive, strong, unitary tappet, in one form of the inventioninvolves the casting of these tappets either singly or in groups. thesame, whether one tappet, or more, is made at a time. A pattern is made,either for a single tappet or for several, and the pattern is so shapedas to provide in the mold not merely the cavity for the casting of thetappet but to provide also spaces or cavities to hold a core by means ofwhich the hollow interior and the ports of the tappet may be formed. Inordinary practice the mold is a green sand mold. In this the tappetcavity is formed by the pattern or patterns and then the cores, whichmay be of any suitable design or material, are put in place and themetal is cast. As shown in Figure 6, a cast iron chill plate is used sothat the working faces or heads serve the purpose of lightening thetappet, providing better lubrication for the side walls and permittingthe support of the core during casting and its removal thereafter. Inthe particular method of manufacture illustrated, the tappet is cast onits side, with a continuous core serving all tappets on one side of themold, and a chill plate is provided to chill the cam-contacting faces.What might be called the side ports in the tappets are formed by theconnecting link portions G of the continuous core, and the upper andlower ports may be formed by the core or by the mold.

The invention is not necessarily limited to the particular method offorming the tappet above outlined and illustrated in the drawing. Themethod of casting isa satisfactory and economical method of forming thetappet and it is described herein for a better understanding of thedevice, but the invention is not limited to it and the The steps ofcasting are essentiallysteps of the method of forming it are not claimedin the present case.

I claim:

l. A valve tappet for engines comprising a hollow cylindrical memberclosed at each end and means for raising lubricant by said tappet, saidmeans comprising the closure for one end of said tappet, the cylindricalwall being relatively thin and integrally united with the substantiallythicker end walls, said cylindrical wall being provided with a pluralityof relatively large cooling and lubricating apertures extendingtherethrough, the apertures being disposed in substantiallydiametrically opposed pairs, there being at least one pair of saidapertures adjacent toeach end wall of the tappet, the apertures adjacentopposite ends of the tappet being in free communication with each otherthrough the hollow interior of the tappet.

2. A valve tappet for engines comprising a hollow, cylindricalsubstantially cage-like body having endwalls of substantial thickness,the cylindrical walls of the body being relatively thin and providedwith a plurality of relatively large perforations separated byrelatively narrow bridges of metal, the lower end of the tappet beingclosed by a lubricant carrying bottom member, the upper end of thetappet being also substantially closed.

3. In a valve tappet for engines, means for cooling and lubricating saidtappet, and means for raising, retaining and discharging lubricant fromsaid tappet, comprising a hollow cylindrical wall member, a closure forone end of said member,

said closure comprising a relatively thickened wall and being providedon its outside with a surface suitable for contact with a tappetoperating means, the diameter of said closure being the same as theoutside diameter oi said cylindrical wall, the cylindrical wall beingformed of relatively thin material integrally united at itsedges withsaid closure and being provided with a plu-v rality, of freely openports, some ports being adjacent each end of the wall, said closurecomprising said lubricant raising member and the cylindrical wallcomprising said lubricant retaining member.

4. In combination, a tappet and a tappet guide, the tappet includinglubricant raising and distributing means, and a. cylindrical wall,freely ported and being closed at its lower end by a thickened memberwhich comprises said lubricant raising means and is provided on itsoutside with a surface suitable for contact with a tappet operatingmeans, the outside diameter of the closing member and of the cylinderbeing the same, the cylinder being freely ported with ports adjacent itstop and bottom, the proportions of the guide and tappet being such thatin the lower position of the tappet a lower port is uncovered and in theupper position of the tappet an upper port is uncovered, whereby freelubricant and air circulation into and through the body of the tappet isprovided, the cylindrical wall co-operating with saidclosure member toretain lubricant upon the end closure.

WEBSTER D. CORLE'I'I.

